RF Front End Module Filter Segmentation for Intermodulation Distortion

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Radio frequency front end modules experience decreased reception sensitivity due to intermodulation distortion caused by simultaneously transmitting radio frequency signals from different communication channels in the same communication band, which affects carrier aggregation technologies like Dual Connectivity (DC) for 4G and 5G communication.

Innovation Solution

A radio frequency front end module configuration that includes a common terminal for both transmission and reception, a power amplifier, a multiplexer with transmission and reception filter units, and a transmission filter arranged between the power amplifier and multiplexer, which treats the transmission bandwidth as a pass band and the reception bandwidth as an attenuation band to mitigate intermodulation distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If radio frequency signals of different communication channels are simultaneously transmitted in the same communication band, then carrier aggregation capability is improved, but intermodulation distortion occurs causing reception sensitivity degradation

Engineering Contradiction:

Improvecarrier aggregation capabilityVSAvoidreception sensitivity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the filter into multiple frequency regions with different characteristics. The first region has a first slope for suppressing intermodulation distortion components, while the second region has a second slope for maintaining reception sensitivity. This segmentation allows simultaneous transmission of multiple channels while preventing distortion from degrading reception performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different filter characteristics to different frequency regions. In the first frequency region, the filter provides stronger suppression (first slope) targeting intermodulation distortion components. In the second frequency region, the filter maintains better passband characteristics (second slope) to preserve reception sensitivity. This local quality approach resolves the contradiction by optimizing each region for its specific requirement.

Inventive Principle:

Principle #3Local quality

2Reliability

If a filter with strong suppression characteristic is used to reduce intermodulation distortion, then reception sensitivity is improved, but transmission signal attenuation increases

Engineering Contradiction:

Improvereception sensitivityVSAvoidtransmission signal strength

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The filter is segmented into multiple frequency regions where each region has optimized characteristics. The first region targets intermodulation distortion suppression while the second region maintains transmission signal integrity. This segmentation prevents excessive attenuation of transmission signals while still achieving reception sensitivity improvement through targeted suppression of distortion components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different filter slopes are applied locally to different frequency regions. The first slope in the first region provides strong suppression for distortion components without affecting transmission power. The second slope in the second region maintains better passband characteristics to prevent transmission signal attenuation. This local optimization resolves the power-sensitivity tradeoff.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration effectively suppresses the degradation of reception sensitivity caused by intermodulation distortion, enhancing the flexibility of carrier aggregation and maintaining high reception sensitivity without limiting the combination of communication channels or transmission power.

Implementation Method 1

intermodulation distortion is caused by a nonlinear element such as a power amplifier, the first and second communication channels differing in frequency

Methodology Applied

Scientific EffectIntermodulation distortion:

Implementation Method 2

a transmission filter that treats a bandwidth including the transmission bandwidth as a pass band and a bandwidth including the reception bandwidth as an attenuation band

Methodology Applied

Scientific EffectFilter attenuation: Filter (electronic)

Data Source

PatentUS11349510B2Radio frequency front end module and communication device

Publication Date: 2022.05.31 MURATA MFG CO LTD

AI summary

A radio frequency (RF) front end module is capable of simultaneously transmitting an RF signal of a first communication channel in a communication band (CB) to which communication channels are allocated and an RF signal of a second communication channel of the CB. The module includes a common terminal, a power amplifier to which RF signals of the first and second communication channels are simultaneously input, a multiplexer that has a transmission filter unit and a reception filter unit connected to the common terminal and treating a transmission bandwidth of the CB and a reception bandwidth of the CB, respectively, as a pass band, and a transmission filter arranged between an output terminal of the power amplifier and an input terminal of the transmission filter unit and treating a bandwidth including the transmission bandwidth as a pass band and a bandwidth including the reception bandwidth as an attenuation band.